Fuel injector and gas turbine

ABSTRACT

A fuel injector includes a premix tube, a fuel introduction unit, and a downstream side plate. The premix tube includes a tube body and a guide part. In the tube body, a through-hole which allows communication between an internal space and an external space is formed at an upstream side end part on a side close to the inlet port. The guide part extends from an end part of the through-hole in a circumferential direction centered on an axis of the premix tube to intersect both the circumferential direction and an axial direction in which the axis extends.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a fuel injector and a gas turbine. Priority is claimed on Japanese Patent Application No. 2018-101761, filed in Japan on May 28, 2018, the content of which is incorporated herein by reference.

Description of Related Art

In a fuel injector such as a gas turbine or a boiler, an air-fuel mixture in which compressed air and fuel gas are mixed in advance is supplied to a combustor in many cases.

Patent Document 1 discloses a fuel injector that ejects an air-fuel mixture in which compressed air and fuel gas are mixed from a plurality of ejection holes regularly formed on a circular substrate.

PATENT DOCUMENTS

[Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2016-080214

SUMMARY OF INVENTION

In the fuel injector as described in Patent Document 1, it is desired to uniformly mix compressed air and fuel gas in order to reduce NOx (nitrogen oxides). Specifically, it is preferable that the compressed air and the fuel gas be in a state in which they are uniformly mixed before reaching a plurality of ejection holes of the fuel injector.

However, when the air and the fuel gas are mixed by injecting the fuel gas into the air using a premix tube, a length of the premix tube needs to be increased in order to sufficiently mix the air and the fuel gas. When the length of the premix tube is increased, costs of parts may increase or combustion stability may decrease to cause combustion oscillations.

An objective of the present invention is to provide a fuel injector and a gas turbine capable of sufficiently mixing air and fuel gas while inhibiting an increase in length of a premix tube.

According to a first aspect of the present invention, a fuel injector includes a premix tube, a fuel introduction unit, and a downstream side plate. The premix tube introduces air from an inlet port into an internal space. The premix tube discharges an air-fuel mixture in which air and fuel are mixed from a discharge port. The fuel introduction unit introduces fuel into the internal space. An end part of the premix tube on the discharge port side penetrates through the downstream side plate. The downstream side plate supports the end part on a downstream side of the premix tube. The premix tube includes a tube body and a guide part. In the tube body, a through-hole which allows communication between an internal space and an external space is formed at an upstream side end part on a side close to the inlet port. The guide part extends from an end part of the through-hole in a circumferential direction centered on an axis of the premix tube to intersect both the circumferential direction and an axial direction in which the axis extends.

With such a configuration, a portion of the air introduced into the internal space of the premix tube passes through the through-hole formed at the upstream side end part and is introduced into the internal space of the premix tube. At this time, the air is guided by the guide part that extends from the end part of the through-hole in the circumferential direction to intersect both the circumferential direction and the axial direction in which the axis extends. A flow of the air guided by the guide part includes a flow directed in the circumferential direction. Therefore, the flow of the air introduced into the internal space of the premix tube includes a swirling flow around the axis of the premix tube. Therefore, mixing of the air and the fuel is promoted by the swirling flow.

Accordingly, the air and the fuel gas are sufficiently mixed while inhibiting an increase in length of the premix tube.

According to a second aspect of the present invention, the guide part according to the first aspect may include an inner guide part. The inner guide part extends from a first end part of the through-hole in the circumferential direction toward an inner side of the inlet port and toward a side close to a second end part of the through-hole.

When air is guided by the inner guide part configured as described above, the air introduced into the internal space via the through-hole can be caused to swirl in a direction from the first end part toward the second end part of the through-hole in the circumferential direction.

According to a third aspect of the present invention, the guide part according to the first or second aspect may include an outer guide part. The outer guide part extends from the second end part of the through-hole in the circumferential direction toward an outer side of the inlet port and toward a side close to the first end part of the through-hole.

When air is guided by the outer guide part configured as described above, the air introduced into the internal space via the through-hole can be caused to swirl in a direction from the first end part toward the second end part of the through-hole in the circumferential direction.

According to a fourth aspect of the present invention, in the guide part and the through-hole according to any one of the first to third aspects, a plurality of guide parts and through-holes may be provided at intervals in the circumferential direction of the inlet port.

With such a configuration, air can be simultaneously introduced from the plurality of through-holes into the internal space. Since the air introduced into the internal space from the plurality of through-holes is guided by the guide parts extending from the plurality of through-holes, the swirling flow of the air introduced into the internal space can be further strengthened.

According to a fifth aspect of the present invention, the fuel introduction unit according to any one of the first to fourth aspects may include a nozzle. The nozzle is inserted into the internal space from the inlet port and injects fuel from a distal end part thereof.

With such a configuration, when the fuel is injected into the internal space of the premix tube by the nozzle inserted from the inlet port, a swirling flow can be generated in the flow of the air flowing around the nozzle and flowing toward the downstream side. Therefore, the air and the fuel can be sufficiently mixed on the downstream side of the nozzle by the swirling flow and can be discharged from the discharge port.

According to a sixth aspect of the present invention, the fuel introduction unit according to any one of the first to fourth aspects may include the downstream side plate, an upstream side plate, a fuel supply pipe, and a fuel through-hole formation part. The upstream side plate forms a plenum between the upstream side plate, an outer wall of the premix tube, and the downstream side plate. The upstream side plate is disposed closer to the inlet port than to the downstream side plate and includes an upstream side through-hole through which the premix tube passes. A fuel supply pipe supplies fuel to the plenum. The fuel through-hole formation part forms a portion of the outer wall of the premix tube and forms a fuel through-hole penetrating through the outer wall of the premix tube.

With such a configuration, when fuel is supplied from the fuel supply pipe to the plenum and the fuel is supplied from the plenum to the internal space, a swirling flow can be formed in the internal space of the premix tube. Therefore, the fuel supplied from the plenum and air can be sufficiently mixed in the internal space of the premix tube and discharged from the discharge port.

According to a seventh aspect of the present invention, a gas turbine includes the fuel injector according to any one of the first to seventh aspects.

With such a configuration, since air and fuel can be sufficiently mixed, the amount of nitrogen oxides can be reduced. Further, since the entire length of the premix tube can be made small, combustion oscillations can be suppressed.

According to the fuel injector and the gas turbine described above, compressed air and fuel gas can be sufficiently mixed while inhibiting an increase in length of the premix tube.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a configuration view illustrating a schematic configuration of a gas turbine in a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of a fuel injector in the first embodiment of the present invention.

FIG. 3 is an enlarged perspective view of an end part on an upstream side of a tube body of a premix tube in the first embodiment of the present invention.

FIG. 4 is a view of the tube body of the premix tube in the first embodiment of the present invention when viewed from an axial direction.

FIG. 5 is a view corresponding to FIG. 4 in a second embodiment of the present invention.

FIG. 6 is a view illustrating a disposition example of a premix tube in the second embodiment of the present invention.

FIG. 7 is a view corresponding to FIG. 4 in a third embodiment of the present invention.

FIG. 8 is a view corresponding to FIG. 2 in another modified example of the embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION First Embodiment

Next, a fuel injector and a gas turbine in a first embodiment of the present invention will be described on the basis of the drawings.

FIG. 1 is a configuration view illustrating a schematic configuration of the gas turbine in an embodiment of the present invention.

As illustrated in FIG. 1, a gas turbine 100 of the present embodiment includes a compressor 51, a plurality of combustors 52, and a turbine 53.

The compressor 51 compresses outside air Ao and generates compressed air A. The compressor 51 includes a compressor rotor 56, a compressor casing 57, and a plurality of compressor vane rows 58.

The compressor rotor 56 rotates around a gas turbine axis Ar. The compressor rotor 56 includes a compressor rotor shaft 59 and a plurality of compressor blade rows 60. The compressor rotor shaft 59 extends along the gas turbine axis Ar. The plurality of compressor blade rows 60 are attached to the compressor rotor shaft 59.

The compressor casing 57 covers the compressor rotor 56.

The plurality of compressor blade rows 60 are aligned in an axial direction of the gas turbine axis Ar. Each of the compressor blade rows 60 is constituted of a plurality of compressor blades (not illustrated) aligned in a circumferential direction around the gas turbine axis Ar. The compressor vane rows 58 are each disposed on downstream sides of the plurality of compressor blade rows 60.

All of the plurality of compressor vane rows 58 are fixed inside the compressor casing 57. Each of the plurality of compressor vane rows 58 is constituted of a plurality of compressor vanes (not illustrated) aligned in the circumferential direction around the gas turbine axis Ar.

The plurality of combustors 52 generate a combustion gas G at high temperature and high pressure. The plurality of combustors 52 are fixed to an intermediate casing 67. The plurality of combustors 52 are disposed at intervals in the circumferential direction around the gas turbine axis Ar.

Each of the plurality of combustors 52 includes a fuel injector 1 and the combustor liner 69.

The fuel injector 1 generates an air-fuel mixture of the compressed air A compressed by the compressor 51 and a fuel gas F and supplies the air-fuel mixture to the combustor liner 69. The fuel injector 1 is disposed inside an outer shell (not illustrated) of the combustor 52.

The combustor liner 69 burns the air-fuel mixture supplied from the fuel injector 1 and guides the burned combustion gas G to the turbine 53.

The turbine 53 converts thermal energy of the combustion gas G into rotational energy. The turbine 53 includes a turbine rotor 61, a turbine casing 62, and a plurality of turbine vane rows 63. The turbine rotor 61 rotates around the gas turbine axis Ar. The turbine rotor 61 includes a turbine rotor shaft 64 and a plurality of turbine blade rows 65. The turbine rotor shaft 64 extends along the gas turbine axis Ar. The turbine rotor 61 is connected to the compressor rotor 56 described above and constitutes a gas turbine rotor 68 together with the compressor rotor 56. To the gas turbine rotor 68 of the present embodiment, a case in which a generator G is connected as a load is illustrated.

The plurality of turbine blade rows 65 are attached to the turbine rotor shaft 64. The plurality of turbine blade rows 65 are aligned in the axial direction of the gas turbine axis Ar. Each of the plurality of turbine blade rows 65 is constituted of a plurality of turbine blades (not illustrated) aligned in the circumferential direction around the gas turbine axis Ar.

The plurality of turbine vane rows 63 are each disposed on upstream sides of the plurality of turbine blade rows 65. The plurality of turbine vane rows 63 are fixed inside the turbine casing 62. Each of the plurality of turbine vane rows 63 is constituted of a plurality of turbine vanes (not illustrated) aligned in the circumferential direction around the gas turbine axis Ar.

The turbine casing 62 covers the turbine rotor 61. The intermediate casing 67 is disposed between the turbine casing 62 and the compressor casing 57 described above. The intermediate casing 67 is formed in a cylindrical shape with the gas turbine axis Ar as a center.

According to the gas turbine 100 described above, first, the outside air Ao taken into the compressor 51 is compressed by passing through the plurality of compressor vane rows 58 and the compressor blade rows 60 and then becomes the compressed air A at high temperature and high pressure. The compressed air A is mixed with the fuel gas F in the combustor 52. The mixed air-fuel mixture is burned and becomes the combustion gas G at high temperature and high pressure. The combustion gas G passes through the turbine vane rows 63 and the turbine blade rows 65 of the turbine 53. At that time, the turbine rotor shaft 64 is rotationally driven, and the rotational energy is transmitted to the generator G connected to the gas turbine rotor 68. The rotational energy is converted into electrical energy by the generator G and then output.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of the fuel injector according to the first embodiment of the present invention.

As illustrated in FIG. 2, the fuel injector 1 includes a fuel supply pipe 8, a plurality of premix tubes 2, an upstream side plate 3, a downstream side plate 4, and an outer wall 5.

In the following description, a direction in which an axis At of the fuel supply pipe 8 extends is referred to as an axial direction Da. Also, a direction perpendicular to the axis At is referred to as a radial direction Dr, a side away from the axis At in the radial direction Dr is referred to as a radial outer side Dr1, and a side closer to the axis At in the radial direction Dr is referred to as a radial inner side Dr2. Also, a side into which the fuel gas F is introduced in the axial direction Da (left side as viewed in FIG. 2) is referred to as an upstream side Da1, and a side from which the fuel gas F is injected in the axial direction Da (right side as viewed in FIG. 2) is referred to as a downstream side Da2. Further, a circumferential direction around the axis At is simply referred to as a circumferential direction Dc.

The fuel supply pipe 8 forms a flow path which guides the fuel gas F supplied from the outside to a plenum PF (details will be described below). The fuel supply pipe 8 has a tubular shape extending in the axial direction Da. The fuel gas F in the fuel supply pipe 8 flows from the upstream side Da1 toward the downstream side Da2. An end part 8 a on the downstream side Da2 of the fuel supply pipe 8 is supported by the upstream side plate 3 and opens in the plenum PF.

The upstream side plate 3 supports end parts (upstream side end parts) 2 a on the upstream side Da1 of the plurality of premix tubes 2 and the end part 8 a on the downstream side Da2 of the fuel supply pipe 8. The upstream side plate 3 also blocks an opening on the upstream side Da1 of the outer wall 5. The upstream side plate 3 has a disc shape centered on the axis At. The upstream side plate 3 includes a first through-hole 3 a formed at a center of the disc shape and a plurality of second through-holes (upstream side through-holes) 3 b formed around the first through-hole 3 a.

The end part 8 a on the downstream side Da2 of the fuel supply pipe 8 described above is inserted through the first through-hole 3 a. More specifically, the end part 8 a on the downstream side Da2 of the fuel supply pipe 8 is disposed to protrude to the downstream side Da2 of the upstream side plate 3 through the first through-hole 3 a. The end parts 2 a on the upstream side Da1 of the premix tubes 2 are each inserted through the second through-holes 3 b. More specifically, the end parts 2 a on the upstream side Da1 of the premix tubes 2 are each disposed to protrude to the upstream side Da1 of the upstream side plate 3 through the second through-holes 3 b.

The downstream side plate 4 supports end parts 2 b on the downstream side Da2 of the plurality of premix tubes 2. The downstream side plate 4 also blocks an opening on the downstream side Da2 of the outer wall 5. The downstream side plate 4 is formed in a disc shape centered on the axis At and has an outer diameter substantially the same as that of the upstream side plate 3.

The outer wall 5 is formed in a tubular shape that forms the plenum PF inside. More specifically, the outer wall 5 has a cylindrical shape extending in the axial direction Da with the axis At as a center. In the outer wall 5, the opening on the upstream side Da1 is closed by the upstream side plate 3, and the opening on the downstream side Da2 is closed by the downstream side plate 4. That is, the downstream side plate 4 and the upstream side plate 3 are connected with the outer wall 5 therebetween. Thus, the plenum PF accommodating the fuel gas G is defined by a surface 4 a on the upstream side Da1 of the downstream side plate 4, a surface 3 c on the downstream side Da2 of the upstream side plate 3, an inner circumferential surface 5 a of the outer wall 5, and outer circumferential surfaces 2 f of outer walls 2 d of the premix tubes 2.

Each of the premix tube 2 is formed in a cylindrical shape extending in the axial direction Da. The premix tube 2 is configured such that the compressed air A is introduced from an inlet port 2A on the upstream side Da1 and an air-fuel mixture MG in which the compressed air A and the fuel gas F are mixed is discharged from a discharge port 2B on the downstream side Da2. As described above, the end part 2 a on the upstream side Da1 of the premix tube 2 in the present embodiment is supported by the upstream side plate 3, and the end part 2 b on the downstream side Da2 is supported by the downstream side plate 4.

The end part 2 b on the downstream side Da2 of the premix tube 2 exemplified in the first embodiment does not protrude from the downstream side plate 4 to the downstream side Da2 and is disposed at the same position as a surface 4 b on the downstream side Da2 of the downstream side plate 4 in the axial direction Da. In other words, an end surface 2 bt on the downstream side Da2 of the premix tube 2 and the surface 4 b on the downstream side Da2 of the downstream side plate 4 are on the same plane with each other. The end part 2 a on the upstream side Da1 of the premix tube 2 is formed to protrude from the upstream side plate 3 to the upstream side Da1.

The outer wall 2 d of the premix tube 2 includes a fuel through-hole formation part 12 forming a fuel through-hole 12 h that penetrates in the radial direction. In the first embodiment, a fuel supply unit of the present invention is constituted by the downstream side plate 4, the upstream side plate 3, the fuel supply pipe 8, and the fuel through-hole formation part 12 described above.

The fuel through-hole 12 h causes an internal space S1 of the premix tube 2 to communicate with the plenum PF. The fuel gas F accommodated in the plenum PF flows into the internal space S1 of the premix tube 2 through the fuel through-hole 12 h. The fuel through-hole 12 h may have, for example, a circular cross-sectional shape and extends in the radial direction of the premix tube 2. A plurality of fuel through-holes 12 h in the present embodiment are provided at intervals in a circumferential direction of the premix tube 2. Positions of the plurality of fuel through-holes 12 h on the premix tube 2 are the same as each other in the axial direction Da. The fuel through-holes 12 h exemplified in the present embodiment are positioned closer to the inlet port 2A than to a center of the premix tube 2 in the axial direction Da. Further, a direction in which the fuel through-holes 12 h extend is not limited to the radial direction. Also, positions of the fuel through-holes 12 h in the plurality of premix tubes 2 may be different from each other in the axial direction Da.

FIG. 3 is an enlarged perspective view of an end part on the upstream side of the tube body of the premix tube according to the first embodiment of the present invention. FIG. 4 is a view of the tube body of the premix tube according to the first embodiment of the present invention when viewed from the axial direction.

As illustrated in FIGS. 3 and 4, the premix tube 2 includes a tube body 21 and a guide part 22.

The tube body 21 includes a through-hole 23 which allows communication between the internal space S1 and an external space S2 at the end part 2 a on the upstream side Da1 thereof on a side close to the inlet port 2A. In the end part 2 a on the upstream side Da1, the through-hole 23 is formed on the upstream side Da1 of the upstream side plate 3. The through-hole 23 of the present embodiment is formed to be recessed from an end surface 2 at on the upstream side Da1 of the tube body 21 toward the downstream side Da2. More specifically, the through-hole 23 includes a first side part (first end part) 23 a and a second side part (second end part) 23 b which extend in the axial direction Da from the end surface 2 at on the upstream side Da1, and a bottom side part 23 c extending in a circumferential direction (hereinafter simply referred to as a circumferential direction Dc2) around the axis A2 of the tube body 21 to connect end parts on the downstream side Da2 of the first side part 23 a and the second side part 23 b.

A plurality of through-holes 23 are formed at intervals in the circumferential direction Dc2 of the tube body 21. Four through-holes 23 are formed at equal intervals in the circumferential direction Dc2 of the tube body 21 in the present embodiment. A case in which a length Lc1 in the circumferential direction Dc2 of the through-hole 23 is longer than a distance Lc2 between the through-holes 23 adjacent to each other in the circumferential direction Dc2 is exemplified. In the present embodiment, the first side part 23 a is disposed on a first side in the circumferential direction Dc2 of the tube body 21, and the second side part 23 b is disposed on a second side in the circumferential direction Dc2 of the tube body 21. In the through-hole 23 of the present embodiment, the bottom side part 23 c is formed longer than the first side part 23 a and the second side part 23 b. Therefore, when viewed from a radial direction of the tube body 21, the through-hole 23 has a rectangular shape which is long in the circumferential direction Dc2.

The guide part 22 guides the air A introduced into the internal space S1 of the tube body 21 via the through-hole 23 in a swirling direction around the axis A2 of the tube body 21. The guide part 22 of the present embodiment includes an inner guide part 22I. The inner guide part 22I extends from the first side part (first end part) 23 a, which is an end part of the through-hole 23 in the circumferential direction Dc2 around the axis A2 of the tube body 21, to intersect both the circumferential direction Dc2 and the axial direction Da (or, a direction in which the axis A2 extends). The inner guide part 22I is disposed in a range in which the through-hole 23 is formed in the circumferential direction Dc2.

As illustrated in FIG. 4, the inner guide part 22I extends to be inclined with respect to a virtual straight line VL extending in a radial direction with the axis A2 of the tube body 21 as a center. The inner guide part 22I is inclined to approach a center (in other words, the axis A2) of the tube body 21 from the first side part 23 a toward the second side part 23 b. The inner guide part 22I in FIG. 4 extends linearly from the first side part 23 a but may also be formed to be slightly curved.

An angle θ1 formed by a tangent TL1 at an end edge on a radial inner side of the first side part 23 a and the inner guide part 22I may be between 90 degrees and 45 degrees. Also, the angle θ1 may be about 60 degrees. When the angle θ1 is set to about 60 degrees, in a case in which the fuel through-holes 12 h in the axial direction Da are at uniform positions, a position at which the air A and the fuel gas G are sufficiently mixed can be made closer to the inlet port 2A in the axial direction Da.

A length L1 of the inner guide part 22I is smaller than the length Lc1 of the through-hole 23 in the circumferential direction Dc2. Further, the length L1 of the inner guide part 22I may be about half the length Lc1 of the through-hole 23. The inner guide part 22I may be formed, for example, by making a cut in the tube body 21 of the inlet port 2A by cutting work or the like and by performing bending work for a portion of the tube body 21. In this way, the inner guide part 22I can be easily formed.

In the first embodiment described above, a portion of the air A introduced into the internal space S1 of the premix tube 2 passes through the through-hole 23 formed at the end part 2 a on the upstream side Da1 and is introduced into the internal space S1 of the premix tube 2. At this time, the air A is guided by the inner guide part 22I that extends in a direction intersecting both the circumferential direction Dc2 and the axial direction Da from the first side part 23 a which is an end part of the through-hole 23 in the circumferential direction Dc2. A flow of the air A guided by the inner guide part 22I includes a flow directed in the circumferential direction Dc2. Therefore, the flow of the air A introduced into the internal space S1 of the premix tube 2 includes a swirling flow around the axis A2 of the premix tube 2. Therefore, mixing of the air A and the fuel F is promoted by the swirling flow.

As a result, the air A and the fuel F can be sufficiently mixed while inhibiting an increase in the length of the premix tube 2.

The inner guide part 22I in the first embodiment described above extends from the first side part 23 a of the through-hole 23 in the circumferential direction Dc2 toward an inner side of the inlet port 2A and toward a side close to the second side part 23 b of the through-hole 23. Therefore, when the air A is guided by the inner guide part 22I configured as described above, the air A introduced into the internal space S1 via the through-hole 23 can be caused to swirl in a direction from the first side part 23 a toward the second side part 23 b of the through-hole 23 in the circumferential direction Dc2.

A plurality of inner guide parts 22I and through-holes 23 of the first embodiment described above are provided at intervals in the circumferential direction Dc2 of the inlet port 2A. Therefore, the air A can be simultaneously introduced from the plurality of through-holes 23 into the internal space S1. Since the air A introduced into the internal space S1 from the plurality of through-holes 23 is guided by the inner guide parts 22I extending from the plurality of through-holes 23, the swirling flow of the air A introduced into the internal space S1 can be further strengthened.

The upstream side plate 3 of the first embodiment described above forms the plenum PF between the outer wall 2 d of the premix tube 2 and the downstream side plate 4. The upstream side plate 3 is disposed closer to the inlet port 2A than to the downstream side plate 4 and includes the second through-holes 3 b through which the premix tubes 2 pass. The fuel supply pipe 8 supplies the fuel F to the plenum PF. The fuel through-hole formation part 12 forms a portion of the outer wall 2 d of the premix tube and forms the fuel through-hole 12 h penetrating through the outer wall 2 d of the premix tube 2. Therefore, the fuel F is supplied from the fuel supply pipe 8 to the plenum PF, and the fuel F is supplied from the plenum PF to the internal space S1.

Thus, when the fuel F is supplied from the plenum PF through the fuel through-hole 12 h as described above, the swirling flow can be formed in the internal space S1 of the premix tube 2 due to the inner guide part 22I disposed on the upstream side Da1 of the fuel through-hole 12 h. Therefore, the fuel F supplied from the plenum PF and the air A can be sufficiently mixed in the internal space S1 of the premix tube 2 and can be discharged from the discharge port 2B.

Since the gas turbine 100 of the first embodiment includes the fuel injector 1 having the above-described configuration, the air A and the fuel F can be sufficiently mixed, and thus the amount of nitrogen oxides can be reduced. Further, the air A and the fuel F can be sufficiently mixed without making the entire length of the premix tube 2 long. Therefore, the entire length of the premix tube 2 can be made small to suppress combustion oscillation while reducing the amount of nitrogen oxides.

Further, since the guide part 22 (inner guide part 22I) is disposed outside the premix tube 2, an increase in the interval between the adjacent premix tubes 2 due to interference between the guide parts 22 can be inhibited.

Second Embodiment

Next, a second embodiment of the present invention will be described on the basis of the drawings. A fuel injector of the second embodiment differs from the fuel injector 1 of the first embodiment described above only in the configuration of the guide part. Therefore, while referencing FIG. 2, parts the same as those in the first embodiment described above are denoted by the same references, and duplicate description thereof will be omitted.

As in the first embodiment, the fuel injector in the second embodiment includes a fuel supply pipe 8, a plurality of premix tubes 202, an upstream side plate 3, a downstream side plate 4, and an outer wall 5.

FIG. 5 is a view corresponding to FIG. 4 in the second embodiment of the present invention.

As illustrated in FIG. 5, the premix tube 202 is formed in a cylindrical shape extending in an axial direction Da (see FIG. 2). The premix tube 202 includes a tube body 21 and a guide part 22. As in the tube body 21 of the first embodiment, the tube body 21 includes a through-hole 23 which allows communication between an internal space S1 and an external space S2 at an end part 2 a on an upstream side Da1 (see FIG. 2) which is on a side close to an inlet port 2A. The through-hole 23 of the second embodiment is formed to be recessed from an end surface 2 at on the upstream side Da1 of the tube body 21 toward a downstream side Da2 (see FIG. 2). As in the first embodiment, the through-hole 23 includes a first side part 23 a and a second side part 23 b which extend in the axial direction Da from the end surface 2 at on the upstream side Da1, and a bottom side part 23 c extending in a circumferential direction Dc2 to connect end parts on the downstream side Da2 of the first side part 23 a and the second side part 23 b.

A plurality of through-holes 23 are formed at intervals in the circumferential direction Dc2 of the tube body 21. As in the through-holes 23 of the first embodiment, four through-holes 23 formed at equal intervals in the circumferential direction Dc2 of the tube body 21 are exemplified in the second embodiment. Further, in the second embodiment, a case in which a length Lc1 of the through-hole 23 in the circumferential direction Dc2 and a distance Lc2 between the through-holes 23 adjacent to each other in the circumferential direction Dc2 have the same relationship as in the first embodiment is exemplified.

As in the first embodiment described above, the guide part 22 guides air A introduced into the internal space S1 of the tube body 21 via the through-hole 23 in a swirling direction around an axis A2 of the tube body 21. The guide part 22 in the second embodiment includes an outer guide part 22O. The outer guide part 22O extends to intersect both the circumferential direction Dc2 and the axial direction Da from the second side part 23 b. In other words, the outer guide part 22O extends to be inclined with respect to a virtual straight line VL extending in a radial direction DrA with an axis A2 of the tube body 21 as a center.

The outer guide part 22O extends from the second side part 23 b toward an outer side DrA1 in the radial direction DrA and toward a side close to the first side part 23 a in the circumferential direction Dc2 of the tube body 21. Thereby, an end part 22Ot of the outer guide part 22O on a side close to the first side part 23 a is disposed on an outer side of the first side part 23 a or the second side part 23 b in the radial direction Dr2 of the tube body 21. The end part 22Ot of the outer guide part 22O on the side close to the first side part 23 a in the second embodiment is disposed on the radial outer side DrA1 of a tangent TL2 passing through an end edge on the radial outer side DrA1 of the second side part 23 b. Further, the outer guide part 22O may extend in a tangent TL2 direction from the second side part 23 b.

Although a case in which the outer guide part 22O extends linearly from the second side part 23 b when viewed from the axial direction Da has been exemplified, the outer guide part 22O may be formed in a slightly curved shape when viewed from the axial direction Da. As in the inner guide part 22I of the first embodiment, the outer guide part 22O in the second embodiment may be formed by making a cut in the tube body 21 of the inlet port 2A by cutting work or the like and by performing bending work for a portion of the tube body 21. In this way, the outer guide part 22O can be easily formed.

A length L2 of the outer guide part 22O is smaller than the length Lc1 of the through-hole 23 in the circumferential direction Dr2. The length L2 of the outer guide part 22O may be about half the length Lc1 of the through-hole 23.

FIG. 6 is a view illustrating a disposition example of the premix tube in the second embodiment of the present invention.

The plurality of premix tubes 202 of the second embodiment can be disposed as illustrated in FIG. 6. Of the four outer guide parts 22O of the premix tube 202, two predetermined outer guide parts 22O disposed to face each other on opposite sides of the axis A2 of the premix tube 202 are disposed to extend in a first direction D1 perpendicular to the axis A2. Also, the remaining two of the outer guide parts 22O illustrated in FIG. 6 extend in a direction (second direction D2) perpendicular to the axis A2 and the first direction D1. With the disposition as illustrated in FIG. 6, interference between the outer guide parts 22O of the adjacent premix tubes 202 can be suppressed while reducing intervals between the plurality of premix tubes 202.

The outer guide part 22O of the second embodiment described above extends from the second side part 23 b of the through-hole 23 in the circumferential direction Dc2 toward the radial outer side DrA1 and toward the side close to the first side part 23 a of the through-hole 23. Therefore, as in the first embodiment, when the air A is guided by the outer guide part 22O, the air A introduced into the internal space S1 via the through-hole 23 can be caused to swirl in a direction from the first side part 23 a toward the second side part 23 b of the through-hole 23 in the circumferential direction Dc2.

A plurality of outer guide parts 22O and through-holes 23 of the second embodiment described above are provided at intervals in the circumferential direction Dc2. Therefore, the air A can be simultaneously introduced from the plurality of through-holes 23 into the internal space S1. Since the air A introduced into the internal space S1 from the plurality of through-holes 23 is guided by the outer guide parts 22O extending from the plurality of through-holes 23, the swirling flow of the air A introduced into the internal space S1 can be further strengthened.

The guide part 22 (outer guide part 22O) is not disposed in the internal space S1 of the premix tube 202 of the second embodiment. Therefore, for example, an increase in pressure loss of the air A introduced into the internal space S1 of the premix tube 202 can be inhibited.

Third Embodiment

Next, a third embodiment of the present invention will be described on the basis of the drawings. A fuel injector of the third embodiment differs from the first and second embodiments only in the configuration of the guide part. Therefore, while referencing FIG. 2, parts the same as those in the second embodiment described above are denoted by the same references, and duplicate description thereof will be omitted.

FIG. 7 is a view corresponding to FIG. 4 in the third embodiment of the present invention.

As illustrated in FIG. 7, a premix tube 302 of the fuel injector of the third embodiment includes a tube body 21 and a guide part 22.

The tube body 21 includes a through-hole 23 which allows communication between an internal space S1 and an external space S2 at an end part 2 a (see FIG. 2) on an upstream side Da1 thereof.

The guide part 22 guides air A introduced into the internal space S1 of the tube body 21 via the through-hole 23 in a swirling direction around an axis A2 of the tube body 21. The guide part 22 in the third embodiment includes an inner guide part 22I and an outer guide part 22O.

The inner guide part 22I has the same configuration as the inner guide part 22I of the first embodiment described above and extends in a direction intersecting both a circumferential direction Dc2 and an axial direction Da from a first side part 23 a which is an end part of the through-hole 23. That is, the inner guide part 22I extends to be inclined with respect to a virtual straight line VL extending in a radial direction with the axis A2 of the tube body 21 as a center. Further, the inner guide part 22I extends linearly from the first side part 23 a as in the first embodiment but may also be formed to be slightly curved.

The outer guide part 22O has the same configuration as the outer guide part 22O of the second embodiment described above and extends in a direction intersecting both the circumferential direction Dc2 and the axial direction Da from a second side part 23 b which is an end part of the through-hole 23. That is, the outer guide part 22O extends to be inclined with respect to a virtual straight line extending in the radial direction with the axis A2 of the tube body 21 as a center. An inclination angle θ2 of the outer guide part 22O with respect to a tangent TL2 passing through an end edge on an outer side of the second side part 23 b is greater than an inclination angle θ1 of the inner guide part 22I with respect to a tangent TL passing through an end edge on an inner side of the first side part 23 a.

As in the first and second embodiments, the inner guide part 22I and the outer guide part 22O may be formed, for example, by making a cut in the tube body 21 of an inlet port 2A by cutting work or the like and by performing bending work for a portion of the tube body 21. At this time, in the third embodiment, when a notch is formed in the axial direction Da in the vicinity of a center of the through-hole 23 in the circumferential direction Dc2, a portion closer to the first side part 23 a than to the notch may be set as the inner guide part 22I, and a portion close to the second side part 23 b may be set as the outer guide part 22O. In this way, the inner guide part 22I and the outer guide part 22O can be easily formed.

In the third embodiment described above, the guide part 22 includes the inner guide part 22I and the outer guide part 22O. Therefore, the air A passing through the through-hole 23 can be guided by both the inner guide part 22I and the outer guide part 22O. Accordingly, a swirling flow can be more stably generated compared to a case in which the air A is guided by only one of the inner guide part 22I and the outer guide part 22O.

In the third embodiment described above, the inclination angle θ1 of the inner guide part 22I with respect to the tangent TL is greater than the inclination angle θ2 of the outer guide part 22O with respect to the tangent TL2. With such a configuration as above, the air A guided to the inside of the through-hole 23 by the outer guide part 22O collides with the inner guide part 22I in the internal space S1 of the tube body 21 and is guided by the inner guide part 22I. As a result, a flow direction of the air A passing through the through-hole 23 can be directed toward a radial inner side DrA2 in stages by the outer guide part 22O and the inner guide part 22I. As a result, a swirling flow can be generated more smoothly in the internal space S1 of the premix tube 2.

(Another Modified Example)

FIG. 8 is a view corresponding to FIG. 2 in another modified example of the embodiment of the present invention.

In each of the embodiments described above, a case in which a fuel introduction unit supplies the fuel F from the fuel supply pipe 8 to the plenum PF and then the fuel F is supplied from the plenum PF to the internal space S1 has been described as an example. However, a configuration of the fuel introduction unit is not limited to the configuration of the above-described embodiments.

For example, also in a case in which a fuel introduction unit FI includes a fuel nozzle 30 that injects the fuel F from a distal end part 31 as in a fuel injector 101 of another modified example illustrated in FIG. 8, the guide part 22 (not illustrated in FIG. 8) of the first to third embodiments described above is applicable. A plurality of fuel nozzles 30 are provided and extend in the axial direction Da similarly to the premix tube 2. The fuel nozzles 30 have an outer diameter smaller than an inner diameter of the premix tubes 2, and the fuel nozzles 30 are each inserted into the premix tubes 2. An internal space S1 through which the air A flows is formed between the fuel nozzle 30 and an inner circumferential surface 2 i of the premix tube 2. Further, in the modified example illustrated in FIG. 8, the distal end part 31 of the fuel nozzle 30 is disposed at a position closer to the inlet port 2A than to a center of the premix tube 2 in the axial direction Da.

With such a configuration as the fuel injector 101 of the present modified example, as in the first to third embodiments described above, the air A introduced into the internal space S1 from the through-hole 23 formed at the end part 2 a on the upstream side can be guided by the guide part 22 to generate a swirling flow. The flow including the swirling flow flows toward the discharge port 2B through the internal space S1 formed between the inner circumferential surface 2 i and an outer circumferential surface 30 f of the fuel nozzle 30. Then, the fuel F injected from the distal end part 31 of the fuel nozzle 30 is mixed with the air A including the swirling flow. Thereafter, mixing of the air A and the fuel F proceeds due to the swirling flow toward the discharge port 2B, and a sufficiently mixed air-fuel mixture MG is discharged from the discharge port 2B.

The present invention is not limited to the configuration of each of the embodiments described above, and modifications can be made in design without departing from the gist of the present invention.

For example, in each of the embodiments described above, a case in which the fuel injector 1 or 101 is used for the gas turbine 100 has been described. However, the present invention is not limited to the gas turbine 100. For example, the fuel injector 1 or 101 may be applied to a boiler, a burner, or the like other than the gas turbine 100.

In each of the embodiments described above, a case in which the inner guide part 22I or the outer guide part 22O which is linear when viewed from the axial direction Da is provided as the guide part 22 has been described. However, the guide part 22 is not limited to the shape of each of the embodiments described above and need only extend to intersect both the circumferential direction Dc2 and the axial direction Da. The inner guide part 22I and the outer guide part 22O may have other shapes such as, for example, a shape in which a straight line and a curve are combined or the like.

In each of the embodiments described above, a case in which the through-hole 23 is formed in a rectangular shape which is long in the circumferential direction Dc2 when viewed from the radial outer side DrA2 has been described. However, the shape of the through-hole 23 is not limited to the above-described shape and may be any shape as long as the air A can be introduced from the radial outer side DrA2.

While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description and is only limited by the scope of the appended claims.

EXPLANATION OF REFERENCES

1, 101 Fuel injector

2, 202, 302 Premix tube

2 a End part (upstream side end part)

2A Inlet port

2 at End surface

2 b End part

2B Discharge port

2 bt End surface

2 d Outer wall

2 f Outer circumferential surface

2 i Inner circumferential surface

3 Upstream side plate

3 a First through-hole

3 b Second through-hole (upstream side through-hole)

3 c Surface

4 Downstream side plate

4 a Surface

4 b Surface

5 Outer wall

5 a Inner circumferential surface

8 Fuel supply pipe

8 a End part

12 Fuel through-hole formation part

12 h Fuel through-hole

21 Tube body

22 Guide part

22I Inner guide part

22O Outer guide part

22Ot End part

23 Through-hole

23 a First side part (first end part)

23 b Second side part (second end part)

23 c Bottom side part

30 Fuel nozzle

30 f Outer circumferential surface

31 Distal end part

51 Compressor

52 Combustor

53 Turbine

56 Compressor rotor

57 Compressor casing

58 Compressor vane row

59 Compressor rotor shaft

60 Compressor blade row

61 Turbine rotor

62 Turbine casing

63 Turbine vane row

64 Turbine rotor shaft

65 Turbine blade row

67 Intermediate casing

68 Gas turbine rotor

69 Combustor liner

100 Gas turbine 

What is claimed is:
 1. A fuel injector, comprising: a premix tube which introduces air from an inlet port into an internal space and discharges an air-fuel mixture in which the air and fuel are mixed from a discharge port; a fuel introduction unit which introduces fuel into the internal space; and a downstream side plate through which an end part on the discharge port side of the premix tube penetrates and which supports the end part on a downstream side of the premix tube; wherein the premix tube includes: a tube body in which a through-hole which allows communication between the internal space and an external space is formed at an upstream side end part on a side close to the inlet port; and a guide part which extends from an end part of the through-hole in a circumferential direction centered on an axis of the premix tube to intersect both the circumferential direction and an axial direction in which the axis extends.
 2. The fuel injector according to claim 1, wherein the guide part includes an inner guide part extending from a first end part of the through-hole in the circumferential direction toward an inner side of the inlet port and toward a side close to a second end part of the through-hole.
 3. The fuel injector according to claim 1, wherein the guide part includes an outer guide part extending from a second end part of the through-hole in the circumferential direction toward an outer side of the inlet port and toward a side close to a first end part of the through-hole.
 4. The fuel injector according to claim 1, wherein a plurality of guide parts and through-holes are provided at intervals in the circumferential direction of the inlet port.
 5. The fuel injector according to claim 1, wherein the fuel introduction unit includes a nozzle inserted into the internal space from the inlet port and configured to inject fuel from a distal end part thereof.
 6. The fuel injector according to claim 1, wherein the fuel introduction unit includes: the downstream side plate; an upstream side plate disposed closer to the inlet port than to the downstream side plate, having an upstream side through-hole through which the premix tube passes, and configured to form a plenum between the upstream side plate, an outer wall of the premix tube, and the downstream side plate; a fuel supply pipe which supplies fuel to the plenum; and a fuel through-hole formation part forming a portion of the outer wall of the premix tube and forming a fuel through-hole penetrating through the outer wall of the premix tube.
 7. A gas turbine comprising the fuel injector according to claim
 1. 8. The fuel injector according to claim 2, wherein the guide part includes an outer guide part extending from a second end part of the through-hole in the circumferential direction toward an outer side of the inlet port and toward a side close to a first end part of the through-hole.
 9. The fuel injector according to claim 2, wherein a plurality of guide parts and through-holes are provided at intervals in the circumferential direction of the inlet port.
 10. The fuel injector according to claim 3, wherein a plurality of guide parts and through-holes are provided at intervals in the circumferential direction of the inlet port.
 11. The fuel injector according to claim 2, wherein the fuel introduction unit includes a nozzle inserted into the internal space from the inlet port and configured to inject fuel from a distal end part thereof.
 12. The fuel injector according to claim 3, wherein the fuel introduction unit includes a nozzle inserted into the internal space from the inlet port and configured to inject fuel from a distal end part thereof.
 13. The fuel injector according to claim 4, wherein the fuel introduction unit includes a nozzle inserted into the internal space from the inlet port and configured to inject fuel from a distal end part thereof.
 14. The fuel injector according to claim 2, wherein the fuel introduction unit includes: the downstream side plate; an upstream side plate disposed closer to the inlet port than to the downstream side plate, having an upstream side through-hole through which the premix tube passes, and configured to form a plenum between the upstream side plate, an outer wall of the premix tube, and the downstream side plate; a fuel supply pipe which supplies fuel to the plenum; and a fuel through-hole formation part forming a portion of the outer wall of the premix tube and forming a fuel through-hole penetrating through the outer wall of the premix tube.
 15. The fuel injector according to claim 3, wherein the fuel introduction unit includes: the downstream side plate; an upstream side plate disposed closer to the inlet port than to the downstream side plate, having an upstream side through-hole through which the premix tube passes, and configured to form a plenum between the upstream side plate, an outer wall of the premix tube, and the downstream side plate; a fuel supply pipe which supplies fuel to the plenum; and a fuel through-hole formation part forming a portion of the outer wall of the premix tube and forming a fuel through-hole penetrating through the outer wall of the premix tube.
 16. The fuel injector according to claim 4, wherein the fuel introduction unit includes: the downstream side plate; an upstream side plate disposed closer to the inlet port than to the downstream side plate, having an upstream side through-hole through which the premix tube passes, and configured to form a plenum between the upstream side plate, an outer wall of the premix tube, and the downstream side plate; a fuel supply pipe which supplies fuel to the plenum; and a fuel through-hole formation part forming a portion of the outer wall of the premix tube and forming a fuel through-hole penetrating through the outer wall of the premix tube.
 17. A gas turbine comprising the fuel injector according to claim
 2. 18. A gas turbine comprising the fuel injector according to claim
 3. 19. A gas turbine comprising the fuel injector according to claim
 4. 20. A gas turbine comprising the fuel injector according to claim
 5. 